Training your glutes is very important for increasing your overall fitness and so people either train it using machines or free weights. But for most of your body, using gym machines for glutes training is a better option due to following reason-

Machines are considered to be great for isolation as you can just target the critical muscles without engaging your lower back like you would with free weights.
Machines give you more control and precision during your lift and with free weights, you are more likely to jerk or swing.